St Bilo's Church, is an active parish church in the village of Llanfilo, Felin-fach, Powys, Wales. The dedication is to Bilo, one of the 24 children of Brychan, a legendary 5th-century king of Brycheiniog. Dating from the 12th century, with later additions, the church was restored by W. D. Caröe in the early 20th century. St Bilo's is designated by Cadw as a Grade I listed building.

The present Church of St Bilo dates from the 12-15th centuries. The Church in Wales Historic Record for the building notes the tradition that the building is of Norman origin. Cadw suggests that two small lintels may be of this date, or earlier. The Clwyd-Powys Archaeological Trust survey undertaken in 1996 did not find built evidence for such an early date. The tower was completely rebuilt in 1882. It was sensitively restored in the early 20th century by W. D. Caröe. A further renovation by the Caröe architectural practice took place in took place in 1992.

The church remains an active parish church in the Diocese of Swansea and Brecon and occasional services are held.

St Bilo's has been described as "rivalling Patrishow and Llanelieu in it beauty, peace and holiness". It consists of a nave, chancel, West tower, and South porch. The church holds a notable 16th-century rood screen and loft, and the Royal Commission on the Ancient and Historical Monuments of Wales records the "splendid ribbed barrel roof". Robert Scourfield and Richard Haslam, in their Powys volume in the Buildings of Wales series, note the substantial collection of wall-mounted 18th century memorial stones.

St Bilo's is as a Grade I listed building. Its lychgate, one of the oldest in Wales and dating from around 1700, a sundial in the churchyard and the former rectory, are all listed at Grade II.

• Scourfield, Robert; Haslam, Richard (2013). Powys: Montgomeryshire, Radnorshire and Breconshire. The Buildings of Wales. New Haven, US and London: Yale University Press. ISBN 978-0-300-18508-9.

• RCAHMW Coflein photographic record